While many advances have been made in surgical techniques in the medical field, the rapid and almost instantaneous control of bleeding within a patient is still lacking. For instance, during arthroscopic procedures in which either calcified material, e.g. bone spurs, and or torn cartilage or ligaments, a cannula is typically inserted into the location at which the surgical procedure is to be performed. Tissue shaving or bone cutting tools are subsequently inserted through the cannula and used in the surgery. During the use of these instruments, no matter how careful the surgeon is during the cutting activity, it is inevitable that a blood vessel is cut by one of the shaving or burring instruments.
Upon the severing of a blood vessel, the field of view is rapidly obscured by bleeding. Using conventional cannulas currently available, the surgeon is required to remove either the shaving or burring instrument from the existing sheath, and insert a long pencil-tipped coagulating device to stop the bleeding. During the time it takes to make this exchange of instruments, the field of view frequently becomes so bloody as to no longer be able to identify the source of the bleeding or the cut blood vessel. Time is of the essence when it relates to cauterizing bleeding blood vessels, and in fact, even being able to see the bleeding vessel to cauterize, is typically impossible even after only a few seconds.
Electrocautery processes are known in the art, such as that shown in U.S. Pat. No. 3,336,916 which illustrates the ability to reduce hemmorrhage during the insertion or withdrawal of material through a cannula. However, this procedure instructs that the usefulness of the technique occurrs during the withdrawal of the cannula from the body, and that the general tip-end of the cannula seals the potential bleeding spots along the entire path made by the outer needle. There is no recognition or teaching of the need for pin-point electrocautery control associated with joint surgery utilizing motorized burring and shaving instruments.
Antishock, anticlog suction coagulators, such as that shown in U.S. Pat. No. 4,932,952 are also known in the art. However, with cannulas of this type, the concern is with the anticlog features of the cannula during a blood suction procedure, and not for pin-point control of bleeding vessels cauterized prior to the cavity being consumed with blood, thereby necessitating the use of a cannula such as that described by Wojciechowicz, Jr.
As is seen from the above discussion, there is no currently available coagulating device in the field of endoscopic or arthroscopic surgery that allows the electrocautery to be positioned on a tube which allows the entrance of other devices, primarily devices which would be geared toward the shaving of tissue or the cutting of bone. All other existing coagulating devices must be passed through a cannula.
As will become evident from subsequent discussions, a coagulating cannula merges two distinct fields of art. First it builds upon existing technology to coagulate blood vessels, and secondly, capitalizes upon existing technology teaches the shaving, cutting and burring of tissues. These two areas represent entirely separate technologies, and the merger of the two into a single instrument represents a significant improvement over the prior art.